Laser processing device and laser processing system

ABSTRACT

An object is to provide a laser processing device and a laser processing system capable of measuring a distance between a work and a processing head accurately and simply and capable of checking the quality of processing in real time during the processing. Provided are: a photodetector that detects the intensity of a processing laser beam split by optical path splitting means, and outputs a detection signal having a signal intensity responsive to the detected intensity together with a time of detection of the intensity; a signal intensity comparing unit that compares the signal intensities of multiple detection signals received from the photodetector; and a detection time comparing unit that compares times of detection of multiple intensities. The signal intensity comparing unit measures a processing quality by comparing the signal intensity of a detection signal received from the photodetector responsive to an incident beam on a work and the signal intensity of a detection signal received from the photodetector responsive to a reflected beam from the work. The detection time comparing unit measures a distance between a laser processing device and the work by comparing times of detection of the intensities.

This application is a Divisional of U.S. application Ser. No. 15/642,558filed Jul. 6, 2017, and is based on and claims the benefit of priorityfrom Japanese Patent Application No. 2016-138626, filed on 13 Jul. 2016,the content of which is incorporated herein by reference.

BACKGROUND OF THE INVENTION Field of the Invention

The present invention relates to a laser processing device and a laserprocessing system for processing of a work using a processing laserbeam.

Related Art

For laser processing using a laser processing head, a distance between awork and the processing head has been required to be controlled so as toplace a focal position of an optical system on the work. A distancebetween the processing head and the work has not been maintainedconstantly, particularly in the application of the processing head toremote laser welding performed with a galvanometer scanner gripped by arobot, for example. Hence, for proper processing, the aforementioneddistance has been required to be measured and the focal position hasbeen required to be controlled to conform to the measured distance.Further, ability to check the quality of processing in real time duringthe processing has been required in terms of reducing takt time andquality management.

The above-described problem may be solved by a method disclosed bypatent document 1, for example. According to this method, the positionof a galvanometer scanner gripped by a robot is measured based on theposition of the tip of a hand of the robot. Patent document 2 disclosesa method of measuring a distance between a work and a processing head byinstalling a laser for measurement inside the processing head. There hasbeen a different method of measuring a distance between a work and aprocessing head by installing a measuring instrument outside theprocessing head.

-   Patent Document 1: Japanese Patent No. 4792901-   Patent Document 2: Japanese Unexamined Patent Application,    Publication No. 2016-000421

SUMMARY OF THE INVENTION

However, the method of patent document 1 finds it difficult to measure adistance between a work and a processing head accurately inconsideration of absolute position accuracy of the robot orrepeatability. The method of patent document 2 necessitates installationof a light source for distance measurement inside the processing headseparately from a light source for processing. This involves a problemof cost increase and a problem relating to space in the processing head.Regarding the method of installing the measuring instrument outside theprocessing head, simply measuring a distance between the work and theprocessing head is made difficult by the necessity to provide themeasuring instrument separately. Further, the methods described abovehave not been devised on condition that the quality of processing bechecked in real time during the processing.

It is therefore an object of the present invention to provide a laserprocessing device and a laser processing system capable of measuring adistance between a work and a processing head accurately and simply andcapable of checking the quality of processing in real time during theprocessing.

(1) A laser processing device according to the present invention is alaser processing device (laser processing device 100 described later,for example) for processing of a work using a processing laser beam. Thelaser processing device comprises: at least one optical path splittingmeans (optical path splitting means 110-1, 110-2, 110-3, 110-4 describedlater, for example) that splits the processing laser beam; aphotodetector (photodetector 130 described later, for example) thatdetects the intensity of the processing laser beam split by the opticalpath splitting means, and outputs a detection signal having a signalintensity responsive to the detected intensity together with a time ofdetection of the intensity; a signal intensity comparing unit (signalintensity comparing unit 140 described later, for example) that comparesthe signal intensities of multiple detection signals each being thedetection signal received from the photodetector; and a detection timecomparing unit (detection time comparing unit 150 described later, forexample) that compares times of detection of multiple intensities eachbeing the intensity received from the photodetector. The signalintensity comparing unit measures a processing quality by comparing thesignal intensity of a detection signal received from the photodetectorresponsive to an incident beam on the work resulting from splitting bythe optical path splitting means and the signal intensity of a detectionsignal received from the photodetector responsive to a reflected beamfrom the work resulting from splitting by the optical path splittingmeans. The detection time comparing unit measures a distance between thelaser processing device and the work by comparing a time of detection ofan intensity received from the photodetector responsive to the incidentbeam and a time of detection of an intensity received from thephotodetector responsive to the reflected beam.

(2) In the laser processing device according to (1), the photodetector(photodetector 330-1, 330-2 described later, for example) of the laserprocessing device (laser processing device 300 described later, forexample) may include two or more photodetectors, at least one of thephotodetectors may detect the intensity of the incident beam, and atleast one of the photodetectors may detect the intensity of thereflected beam.

(3) In the laser processing device according to (1) or (2), the signalintensity comparing unit (signal intensity comparing unit 140, 340described later, for example) may measure a difference or a ratiobetween the signal intensity of the detection signal responsive to theincident beam and the signal intensity of the detection signalresponsive to the reflected beam.

(4) A first laser processing system according to the present invention(laser processing system 200 described later, for example) comprises alaser oscillator (laser oscillator 220 described later, for example), anoscillator controller (oscillator controller 210 described later, forexample) that controls the laser oscillator, and a laser processingdevice (laser processing device 230 described later, for example) forprocessing of a work using a processing laser beam oscillated by thelaser oscillator. The laser processing device comprises: at least oneoptical path splitting means (optical path splitting means 240-1, 240-2,240-3, 240-4 described later, for example) that splits the processinglaser beam; and a photodetector (photodetector 260 described later, forexample) that detects the intensity of the processing laser beam splitby the optical path splitting means, and outputs a detection signalhaving a signal intensity responsive to the detected intensity togetherwith a time of detection of the intensity. The laser processing systemfurther comprises a signal intensity comparing device (signal intensitycomparing device 270 described later, for example) and a detection timecomparing device (detection time comparing device 280 described later,for example). The signal intensity comparing device compares the signalintensities of multiple detection signals each being the detectionsignal received from the photodetector. The detection time comparingdevice compares times of detection of multiple intensities each beingthe intensity received from the photodetector. The signal intensitycomparing device measures a processing quality by comparing the signalintensity of a detection signal received from the photodetectorresponsive to an incident beam on the work resulting from splitting bythe optical path splitting means and the signal intensity of a detectionsignal received from the photodetector responsive to a reflected beamfrom the work resulting from splitting by the optical path splittingmeans. The detection time comparing device measures a distance betweenthe laser processing device and the work by comparing a time ofdetection of an intensity received from the photodetector responsive tothe incident beam and a time of detection of an intensity received fromthe photodetector responsive to the reflected beam.

(5) In the laser processing system according to (4), the photodetectorof the laser processing device may include two or more photodetectors,at least one of the photodetectors may detect the intensity of theincident beam, and at least one of the photodetectors may detect theintensity of the reflected beam.

(6) A second laser processing system according to the present invention(laser processing system 400 described later, for example) comprises alaser oscillator (laser oscillator 420 described later, for example), anoscillator controller (oscillator controller 410 described later, forexample) that controls the laser oscillator, and a laser processingdevice (laser processing device 430 described later, for example) forprocessing of a work using a processing laser beam oscillated by thelaser oscillator. The laser processing device comprises: at least oneoptical path splitting means (optical path splitting means 440 describedlater, for example) that splits the processing laser beam; and aphotodetector (photodetector 460 described later, for example) thatdetects the intensity of the processing laser beam split by the opticalpath splitting means, and outputs a detection signal having a signalintensity responsive to the detected intensity together with a time ofdetection of the intensity. The laser processing system furthercomprises a signal intensity comparing device (signal intensitycomparing device 470 described later, for example) and a detection timecomparing device (detection time comparing device 480 described later,for example). The signal intensity comparing device compares the signalintensity of the detection signal received from the photodetector withan intensity command value transmitted from the oscillator controller tothe laser oscillator. The detection time comparing device compares thetime of detection of the intensity received from the photodetector withan oscillation command time transmitted from the oscillator controllerto the laser oscillator. The signal intensity comparing device measuresa processing quality by comparing the signal intensity of the detectionsignal received from the photodetector responsive to a reflected beamfrom the work resulting from splitting by the optical path splittingmeans with the intensity command value. The detection time comparingdevice measures a distance between the laser processing device and thework by comparing the time of detection of the intensity received fromthe photodetector responsive to the reflected beam with the oscillationcommand time.

(7) In the laser processing system described in (4) to (6), the signalintensity comparing device may measure a difference or a ratio betweenthe signal intensity of the detection signal responsive to the incidentbeam or the intensity command value and the signal intensity of thedetection signal responsive to the reflected beam.

According to the present invention, by using a light source forprocessing as a light source for measurement, a distance between a workand a processing head can be measured and a processing quality can bechecked at the same time.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows the configuration of a laser processing device entirelyaccording to a first embodiment;

FIG. 2 shows the configuration of a laser processing system entirelyaccording to a second embodiment;

FIG. 3 shows the configuration of a laser processing device entirelyaccording to a third embodiment; and

FIG. 4 shows the configuration of a laser processing system entirelyaccording to a fourth embodiment.

DETAILED DESCRIPTION OF THE INVENTION First Embodiment

A first embodiment of the present invention will be described in detailby referring to FIG. 1.

For laser processing using a laser processing device, grasping theposition of the laser processing device and that of a work relative toeach other is important for obtaining a favorable processing quality.According to the present invention, to calculate a distance between thelaser processing device and the work, a time of flight (TOF) method isemployed by using a processing light source. More specifically, thismethod is to measure time of flight of a processing beam from projectionof the processing beam to a subject to receipt of a reflected beam, andto multiply the measured time of flight by the speed of flight of theprocessing beam. Optical path splitting means such as a beam splitter isinstalled for measurement of the time of flight. According to the firstembodiment, an incident beam on a work and a reflected beam from thework both resulting from splitting by the optical path splitting meansare measured, and a distance is measured based on a difference betweentimes of detection of these beams. A photodetector capable of detectinga light intensity is used for measurement of the incident beam on thework and the reflected beam from the work. A time difference betweenincidence of the incident beam on the photodetector and incidence of thereflected beam on the photodetector is determined using times ofdetection of these beams. Further, by comparing a detected intensity ofthe incident beam on the work and that of the reflected beam from thework, change in the intensity of the reflected beam relative to theincident beam can be measured, so that a processing quality can bemeasured based on the state of the reflected beam.

FIG. 1 shows an example of the configuration of a laser processingdevice 100 according to the first embodiment. The laser processingdevice 100 includes four optical path splitting means including 110-1,110-2, 110-3, and 110-4 (these means are collectively called “opticalpath splitting means 110”), a focusing lens 120, a photodetector 130, asignal intensity comparing unit 140, and a detection time comparing unit150.

The optical path splitting means 110 is an optical element that splits abeam in a constant ratio into a transmitted beam and a reflected beam.As described above, a beam splitter is usable as the optical pathsplitting means 110, for example. The center of each of the four opticalpath splitting means 110-1 to 110-4 forms a rectangle. Each of the fouroptical path splitting means 110-1 to 110-4 is arranged in such a mannerthat a normal to each of the front surface and the back surface of eachoptical path splitting means, viewed from an incident beam or from areflected beam, forms an angle of 45 degrees or 135 degrees with a sideof the above-described rectangle. The photodetector 130 includes aphoto-detecting unit not shown in the drawings arranged on a straightlight passing through the center of the optical path splitting means110-1 and that of the optical path splitting means 110-2 and on anopposite side of the optical path splitting means 110-1 across theoptical path splitting means 110-2. The center of the focusing lens 120is arranged on a straight line passing through the center of the opticalpath splitting means 110-1 and that of the optical path splitting means110-3 and on an opposite side of the optical path splitting means 110-1across the optical path splitting means 110-3.

A laser oscillator and an oscillator controller that controls the laseroscillator, both of which are not shown in the drawings, are providedoutside the laser processing device 100. A laser beam emitted from thelaser oscillator and incident on the laser processing device 100 firstreaches the optical path splitting means 110-1. Then, the laser beam ispartially transmitted through the optical path splitting means 110-1 andthe other of the laser beam is reflected. The incident beam reflectedfrom the optical path splitting means 110-1 is transmitted through theoptical path splitting means 110-2 to enter the photodetector 130. Theincident beam transmitted through the optical path splitting means 110-1passes through the optical path splitting means 110-3 and the focusinglens 120 to collide with a work 500. A beam reflected from the work 500passes through the focusing lens 120. Then, the reflected beam isreflected from each of the optical path splitting means 110-3, theoptical path splitting means 110-4, and the optical path splitting means110-2 to reach the photodetector 130. By following the above-describedroutes, both the incident beam on the work 500 and the reflected beamfrom the work 500 enter the photodetector 130.

The photodetector 130 detects the intensities of both of the followingbeams having entered the photodetector 130: the incident beam on thework 500 and the reflected beam from the work 500. The photodetector 130outputs a detection signal having a signal intensity responsive to theintensity of the incident beam on the work 500 together with a time ofdetection of this intensity. Further, the photodetector 130 outputs adetection signal having a signal intensity responsive to the intensityof the reflected beam from the work 500 together with a time ofdetection of this intensity. For example, a photodiode is usable as thephotodetector 130.

The signal intensity comparing unit 140 compares the following signalintensities received from the photodetector 130: the signal intensity ofthe detection signal responsive to the incident beam on the work 500 andthe signal intensity of the detection signal responsive to the reflectedbeam from the work 500. Based on a result of this comparison, the signalintensity comparing unit 140 measures the processing quality of laserprocessing. More specifically, the signal intensity comparing unit 140makes this comparison by calculating a difference or a ratio between thesignal intensity of the detection signal responsive to the incident beamand the signal intensity of the detection signal responsive to thereflected beam.

The detection time comparing unit 150 compares the following detectiontimes received from the photodetector 130: the time of detection of theintensity of the incident beam on the work 500 and the time of detectionof the intensity of the reflected beam from the work 500. Based on aresult of this comparison, the detection time comparing unit 150calculates a distance between the laser processing device 100 and thework 500. More specifically, the detection time comparing unit 150 cancalculate this distance by determining a time difference between thetime of detection of the intensity of the incident beam on the work 500and the time of detection of the intensity of the reflected beam fromthe work 500, and using a result of multiplication of the determinedtime difference by the speed of a processing laser beam.

The operation of the laser processing device 100 as a whole is asfollows. If a processing laser beam emitted from the laser oscillatorprovided outside the laser processing device 100 enters the laserprocessing device 100, the multiple optical path splitting means 110split the incident processing laser beam into a beam to be incident onthe work 500 and a beam to be reflected from the work 500. Both of theseprocessing laser beams enter the photodetector 130. The signal intensitycomparing unit 140 compares the signal intensities of the detectionsignals responsive to the following beams having entered thephotodetector 130: the incident beam on the work 500 and the reflectedbeam from the work 500. A processing quality can be checked based on aresult of this comparison. The detection time comparing unit 150compares the time of detection of the intensity of the incident beam onthe work 500 and the time of detection of the intensity of the reflectedbeam from the work 500. A distance between the laser processing device100 and the work 500 can be measured based on a result of thiscomparison.

According to the above-described first embodiment, a distance betweenthe laser processing device 100 and the work 500 can be calculatedwithout the need of preparing a light source for distance measurementseparately from a light source for processing or a device for distancemeasurement separately from the laser processing device. Further, aprocessing quality can be evaluated together with distance measurement.

Second Embodiment

A second embodiment of the present invention will be described in detailby referring to FIG. 2.

According to the first embodiment, the laser processing device 100includes the signal intensity comparing unit 140 and the detection timecomparing unit 150 as its constituting elements. By contrast, accordingto the second embodiment, instead of providing a signal intensitycomparing unit and a detection time comparing unit to the laserprocessing device 100, a signal intensity comparing device 270 and adetection time comparing device 280 separately from the laser processingdevice 100 are provided.

More specifically, a laser processing system 200 with a laser processingdevice 230 according to the second embodiment includes a laseroscillator 220, an oscillator controller 210 that controls the laseroscillator 220, the signal intensity comparing device 270, and thedetection time comparing device 280 in addition to the laser processingdevice 230.

Like the laser processing device 100 according to the first embodiment,the laser processing device 230 includes four optical path splittingmeans including 240-1, 240-2, 240-3, and 240-4 (these means arecollectively called “optical path splitting means 240”), a focusing lens250, and a photodetector 260. These constituting elements are arrangedin the same positions as those of the corresponding constitutingelements of the laser processing device 100.

A route of a processing laser beam, the function and the operation ofthe optical path splitting means 240, those of the focusing lens 250,and those of the photodetector 260 are the same as those of the firstembodiment, so that they will not be described here. The function andthe operation of the signal intensity comparing device 270 and those ofthe detection time comparing device 280 are the same as those of thesignal intensity comparing unit 140 and those of the detection timecomparing unit 150 respectively, so that they will not be describedhere.

The operation of the laser processing system 200 as a whole is asfollows. If a processing laser beam emitted from the laser oscillator220 provided outside the laser processing device 230 enters the laserprocessing device 230, the multiple optical path splitting means 240split the incident processing laser beam into a beam to be incident onthe work 500 and a beam to be reflected from the work 500. Both of theseprocessing laser beams enter the photodetector 260. The signal intensitycomparing device 270 provided outside the laser processing device 230compares the signal intensities of detection signals responsive to thefollowing beams having entered the photodetector 260: the incident beamon the work 500 and the reflected beam from the work 500. A processingquality can be checked based on a result of this comparison. Thedetection time comparing device 280 provided outside the laserprocessing device 230 compares a time of detection of the intensity ofthe incident beam on the work 500 and a time of detection of theintensity of the reflected beam from the work 500. A distance betweenthe laser processing device 230 and the work 500 can be measured basedon a result of this comparison.

According to the second embodiment, like in the first embodiment, adistance between the laser processing device 230 and the work 500 can becalculated without the need of preparing a light source for distancemeasurement separately from a light source for processing. Further, aprocessing quality can be evaluated together with distance measurement.

Third Embodiment

A third embodiment of the present invention will be described in detailby referring to FIG. 3.

The laser processing device according to each of the first and secondembodiments includes the multiple optical path splitting means. Bycontrast, a laser processing device according to the third embodimentincludes only one optical path splitting means and includes multiplephotodetectors.

FIG. 3 shows an example of the configuration of a laser processingdevice 300 according to the third embodiment. The laser processingdevice 300 includes optical path splitting means 310, a focusing lens320, a photodetector 330-1, a photodetector 330-2, a signal intensitycomparing unit 340, and a detection time comparing unit 350.

Only one optical path splitting means 310 is provided in the laserprocessing device 300. Both the front surface and the back surface ofthe optical path splitting means 310, viewed from an incident beam orfrom a reflected beam, function as reflection surfaces. The optical pathsplitting means 310 is arranged in such a manner that a normal to eachof the front surface and the back surface of the optical path splittingmeans 310 forms an angle of 45 degrees with the incident beam or thereflected beam. Referring to FIG. 3, on the assumption that a processinglaser beam is to enter the laser processing device 300 from above asviewed from the optical path splitting means 310, the photodetector330-1, the photodetector 330-2, and the focusing lens 320 are arrangedto the left and to the right of the optical path splitting means 310,and below the optical path splitting means 310 respectively.

A laser oscillator and an oscillator controller that controls the laseroscillator, both of which are not shown in the drawings, are providedoutside the laser processing device 300. A laser beam emitted from thelaser oscillator and incident on the laser processing device 300 firstreaches the optical path splitting means 310. Then, the laser beam ispartially transmitted through the optical path splitting means 310 andthe other of the laser beam is reflected. The incident beam reflectedfrom the optical path splitting means 310 enters the photodetector330-1. The incident beam transmitted through the optical path splittingmeans 310 passes through the focusing lens 320 to collide with the work500. A beam reflected from the work 500 passes through the focusing lens320. Then, the reflected beam is reflected from the optical pathsplitting means 310 to reach the photodetector 330-2.

The photodetector 330-1 detects the intensity of the incident beam onthe work 500 having entered the photodetector 330-1. The photodetector330-1 outputs a detection signal having a signal intensity responsive tothe intensity of the incident beam on the work 500 together with a timeof detection of this intensity. The photodetector 330-2 detects theintensity of the reflected beam from the work 500 having entered thephotodetector 330-2. The photodetector 330-2 outputs a detection signalhaving a signal intensity responsive to the intensity of the reflectedbeam from the work 500 together with a time of detection of thisintensity.

The signal intensity comparing unit 340 compares the signal intensity ofthe detection signal responsive to the incident beam on the work 500received from the photodetector 330-1 and the signal intensity of thedetection signal responsive to the reflected beam from the work 500received from the photodetector 330-2. Based on a result of thiscomparison, the signal intensity comparing unit 340 measures theprocessing quality of laser processing. More specifically, the signalintensity comparing unit 340 makes this comparison by calculating adifference or a ratio between the signal intensity of the detectionsignal responsive to the incident beam and the signal intensity of thedetection signal responsive to the reflected beam.

The detection time comparing unit 350 compares the time of detection ofthe intensity of the incident beam on the work 500 received from thephotodetector 330-1 and the time of detection of the intensity of thereflected beam from the work 500 received from the photodetector 330-2.Based on a result of this comparison, the detection time comparing unit350 calculates a distance between the laser processing device 300 andthe work 500. More specifically, the detection time comparing unit 350can calculate this distance by determining a time difference between thetime of detection of the intensity of the incident beam on the work 500and the time of detection of the intensity of the reflected beam fromthe work 500, and using a result of multiplication of the determinedtime difference by the speed of a processing laser beam.

The operation of the laser processing device 300 as a whole is asfollows. If a processing laser beam emitted from the laser oscillatorprovided outside the laser processing device 300 enters the laserprocessing device 300, the single optical path splitting means 310splits the incident processing laser beam into a beam to be incident onthe work 500 and a beam to be reflected from the work 500. The incidentbeam on the work 500 enters the photodetector 330-1. The reflected beamfrom the work 500 enters the photodetector 330-2. The signal intensitycomparing unit 340 compares the signal intensity of the detection signalresponsive to the incident beam on the work 500 having entered thephotodetector 330-1 and the signal intensity of the detection signalresponsive to the reflected beam from the work 500 having entered thephotodetector 330-2. A processing quality can be checked based on aresult of this comparison. The detection time comparing unit 350compares the time of detection of the intensity of the incident beam onthe work 500 having entered the photodetector 330-1 and the time ofdetection of the intensity of the reflected beam from the work 500having entered the photodetector 330-2. A distance between the laserprocessing device 300 and the work 500 can be measured based on a resultof this comparison.

According to the above-described third embodiment, a distance betweenthe laser processing device 300 and the work 500 can also be calculatedwithout the need of preparing a light source for distance measurementseparately from a light source for processing or a device for distancemeasurement separately from the laser processing device. Further, aprocessing quality can be evaluated together with distance measurement.Additionally, unlike in the first and second embodiments, the intensityand the time of receipt of the incident beam and those of the reflectedbeam can be acquired by using only one optical path splitting means.

Fourth Embodiment

A fourth embodiment of the present invention will be described in detailby referring to FIG. 4.

According to the first to third embodiments, both the intensity of anincident beam on the work 500 and that of a reflected beam from the work500 are detected. Based on results of the detection about these beams, aprocessing quality and a distance between a laser processing device anda work are measured. According to the fourth embodiment, instead ofusing a result of detection about the intensity of an incident beam, anintensity command value and an oscillation command time of an incidentbeam contained in oscillation command information transmitted from anoscillator controller to a laser oscillator are acquired. Each of theacquired intensity command value and oscillation command time iscompared with a result of detection about the intensity of a reflectedbeam to measure a processing quality and a distance between a laserprocessing device and a work.

FIG. 4 shows an example of the configuration of a laser processingsystem 400 with a laser processing device 430 according to the fourthembodiment. The laser processing system 400 includes a laser oscillator420, an oscillator controller 410 that controls the laser oscillator420, a signal intensity comparing device 470, and a detection timecomparing device 480 in addition to the laser processing device 430.

Like the laser processing device 300 according to the third embodiment,the laser processing device 430 according to the fourth embodimentincludes single optical path splitting means 440. The optical pathsplitting means 440 is arranged in such a manner that a normal to eachof the front surface and the back surface of the optical path splittingmeans 440 forms an angle of 45 degrees with an incident beam or areflected beam. Unlike the laser processing device 300 according to thethird embodiment, the laser processing device 430 according to thefourth embodiment does not include a photodetector that detects anincident beam on the work 500 but only a photodetector 460 that detectsa reflected beam from the work 500 is provided. Specifically, referringto FIG. 4, on the assumption that a processing laser beam is to enterthe laser processing device 430 from above as viewed from the opticalpath splitting means 440, constituting elements include only thephotodetector 460 arranged to the right of the optical path splittingmeans 440 and a focusing lens 450 arranged below the optical pathsplitting means 440 in addition to the optical path splitting means 440.The photodetector 460 detects the intensity of the reflected beam fromthe work 500 having entered the photodetector 460. The photodetector 460outputs a detection signal having a signal intensity responsive to theintensity of the reflected beam from the work 500 together with a timeof detection of this intensity.

Unlike in the laser processing system 200 according to the secondembodiment, in the laser processing system 400 according to the fourthembodiment, the oscillator controller 410 transmits an oscillationcommand containing information about an intensity command value and anoscillation command time of an incident beam to each of the signalintensity comparing device 470 and the detection time comparing device480 as well as to the laser oscillator 420.

The signal intensity comparing device 470 compares the signal intensityof the detection signal responsive to the reflected beam from the work500 received from the photodetector 460 and the intensity command valueof the incident beam on the work 500 received from the oscillatorcontroller 410. Based on a result of this comparison, the signalintensity comparing device 470 measures the processing quality of laserprocessing.

The detection time comparing device 480 compares the time of detectionof the intensity of the reflected beam from the work 500 received fromthe photodetector 460 and the oscillation command time of the incidentbeam on the work 500 received from the oscillator controller 410. Basedon a result of this comparison, the detection time comparing device 480calculates a distance between the laser processing device 430 and thework 500. More specifically, the detection time comparing device 480 cancalculate this distance by determining a time difference between theoscillation command time of the incident beam on the work 500 and thetime of detection of the intensity of the reflected beam from the work500, and using a result of multiplication of the determined timedifference by the speed of a processing laser beam.

The operation of the laser processing system 400 as a whole is asfollows. If a processing laser beam emitted from the laser oscillator420 provided outside the laser processing device 430 enters the laserprocessing device 430, the single optical path splitting means 440splits the incident processing laser beam into a beam to be incident onthe work 500 and a beam to be reflected from the work 500. The reflectedbeam from the work 500 enters the photodetector 460. The signalintensity comparing device 470 compares the signal intensity of thedetection signal responsive to the reflected beam from the work 500having entered the photodetector 460 and the intensity command value ofthe incident beam on the work 500 received from the oscillatorcontroller 410. A processing quality can be checked based on a result ofthis comparison. The detection time comparing device 480 compares thetime of detection of the intensity of the reflected beam from the work500 having entered the photodetector 460 and the oscillation commandtime of the incident beam on the work 500 received from the oscillatorcontroller 410. A distance between the laser processing device 430 andthe work 500 can be measured based on a result of this comparison.

According to the above-described fourth embodiment, a distance betweenthe laser processing device 430 and the work 500 can also be calculatedwithout the need of preparing a light source for distance measurementseparately from a light source for processing or a device for distancemeasurement separately from the laser processing device. Further, aprocessing quality can be evaluated together with distance measurement.Additionally, the intensity and the time of receipt of the incident beamand those of the reflected beam can be acquired by using only oneoptical path splitting means unlike in the first and second embodiments,and by using only one photodetector unlike in the third embodiment.

The present invention is not limited to the embodiments described above.The effects described in the present embodiments are merely given tolist most preferable effects achieved by the present invention. Effectsachieved by the present invention are not to be limited to thosedescribed in the present embodiments.

A method of processing using the laser processing devices 100, 230, 300,and 430, and the laser processing systems 200 and 400 is realized bysoftware. If this method is to be realized by software, programs forconfiguring this software are installed on a computer (laser processingdevice 100, 230, 300, or 430). These programs may be recorded on aremovable medium and then distributed to a user. Alternatively, theseprograms may be distributed to the user by being downloaded to acomputer of the user through a network. Still alternatively, theseprograms may be provided to the computer of the user (laser processingdevice 100, 230, 300, or 430) in the form of web service offered througha network without being downloaded on the computer.

EXPLANATION OF REFERENCE NUMERALS

-   -   100, 230, 300, 430 Laser processing device    -   110-1, 110-2, 110-3, 110-4, 240-1, 240-2, 240-3, 240-4, 310, 440        Optical path splitting means    -   120, 250, 320, 450 Focusing lens    -   130, 260, 330-1, 330-2, 460 Photodetector    -   140, 340 Signal intensity comparing unit    -   150, 350 Detection time comparing unit    -   200, 400 Laser processing system    -   210, 410 Oscillator controller    -   220, 420 Laser oscillator    -   270, 470 Signal intensity comparing device    -   280, 480 Detection time comparing device    -   500 Work

What is claimed is:
 1. A laser processing system comprising a laseroscillator, an oscillator controller that controls the laser oscillator,and a laser processing device for processing of a work using aprocessing laser beam oscillated by the laser oscillator, the laserprocessing device comprising: at least one optical path splitting meansthat splits the processing laser beam; and a photodetector that detectsthe intensity of the processing laser beam split by the optical pathsplitting means, and outputs a detection signal having a signalintensity responsive to the detected intensity together with a time ofdetection of the intensity, the laser processing system furthercomprising a signal intensity comparing device and a detection timecomparing device, the signal intensity comparing device comparing thesignal intensity of the detection signal received from the photodetectorwith an intensity command value transmitted from the oscillatorcontroller to the laser oscillator, the detection time comparing devicecomparing the time of detection of the intensity received from thephotodetector with an oscillation command time transmitted from theoscillator controller to the laser oscillator, the signal intensitycomparing device measuring a processing quality by comparing the signalintensity of the detection signal received from the photodetectorresponsive to a reflected beam from the work resulting from splitting bythe optical path splitting means with the intensity command value, thedetection time comparing device measuring a distance between the laserprocessing device and the work by comparing the time of detection of theintensity received from the photodetector responsive to the reflectedbeam with the oscillation command time.